SPU:Strange Growth

I have never seen this on a spuria iris before. Out of the old spent
bloom stalk is growing a new rhizome, complete with a root about at least an
inch long. This is only one of 3 different plants this has happened
to.

I know that various century plants and onions do this, and the walking iris
also is known for this, but it usually happens where there was a flower, as
opposed to right off the side of a bloom stalk.

Is this normal for spuria iris to do this? Does this happen with other
irises?

I've included a few photos, one with the flash on and two without...from
both sides of the plant.